Prior art systems for containing molten materials, and in particular, molten metals, have relied on refractory lining or water cooling or a combination of both to protect the walls, bottom and covers of such vessels from the high temperature generated by the molten materials and off-gases. In the case of molten metals such as steel, these temperatures may be in excess of 2800.degree. F. (1540.degree. C.).
Refractory linings installed in such vessels are costly and have short lives, even where such linings are utilized above the melt line of the vessel. Although water has been utilized to cool the inner surfaces of these vessels (generally made from structural steel plate) it has been the usual practice to utilize closed systems in which pressurized water completely fills circulating passages within the vessel walls, roof, etc. These systems generally necessitate high volumes of water at relatively high pressures. "Hot spots" created on the inner wall by blockage of coolant water can lead to flashing of the water to steam and rupture of the containment structure. Once leakage occurs in the inner walls of the vessel, the flow of the cooling water into the molten material can lead to serious hazards such as explosions due to the water flashing to steam or other adverse reactions. These problems could create serious hazards to life and equipment. Other prior art systems which seek to alleviate such problems utilize complex, costly and difficult-to-maintain equipment which is clearly not desirable in the surrounding area and environment of steel furnaces and other molten material handling vessels.
U.S. Pat. No. 4,813,055 discloses a spray cooling system for cooling a furnace for the melting or treatment of molten metal, and particularly the roof and/or sidewall of electric-arc, plasma-arc and ladle furnaces. Specifically, spray headers and pipes supply coolant to spray nozzles distributed within a coolant space in a roof structure to spray coolant against the working plates of the roof. The coolant is quickly and effectively removed from the coolant space after it is sprayed against the working plates, thereby avoiding any potentially detrimental movement and localized collection of the coolant in the space.
It is an object of the present invention to provide a cooling system for a removable segment of a cover for a vessel that contains tubes coupled to nozzles arranged to direct a spray of coolant against the surface of the cover that is to be cooled.
It is another object of the present invention to provide a roof for a furance that has a removable delta section that is cooled by spray coolant means.
It is another object of the present invention to provide a removable delta section of a roof that employs removable spray coolant means comprising tubes coupled to nozzles that are arranged to direct a spray of coolant against a surface of the roof that is to be cooled.
It is another object of the present invention to provide a cost effective removable delta for roofs or vessels such as furnaces handling molten materials.
These and other objects of the invention will become apparent upon consideration of the following description viewed in conjunction with the drawings.